Observers will monitor and evaluate the mock journeys to ensure adherence, he added. “If the outcome is not as desired, one has to ask: Is the plan not good enough, or is implementation not good enough?” Dr. Cetron said. “This is a virus that can be very unforgiving of a mistake.”
“We all recognize this virus is a formidable foe, and we’re going to be living with it for a while, and we need to adapt our systems to have maximum impact,” he added.
Ships will have fewer guests than in the past, and both crew members and passengers would be required to wear masks and to maintain social distancing, Dr. Cetron said. At first, new crew members joining a ship would not only be tested before boarding, but also be quarantined for 14 days. The crew would also be quarantined for 14 days before disembarking.
The quarantines would not apply to passengers, however. The C.D.C. said passengers would instead be tested twice before boarding, he said. The guidelines will continue to be improved and “tweaked” along the way, he added.
The world’s major cruise lines have been idled for months under no-sail orders as the pandemic swept around the world, after tourists and crews aboard ships like the Diamond Princess docked and were stranded for weeks as infection rates soared onboard.
Many cruise lines, like Royal Caribbean, had already announced they would not resume sailing until at least December. Some have canceled future sailings — Carnival Cruise, for example, has canceled all sailings through Dec. 31, as well as some sailings in 2021 and 2022. But with cases rising to record levels in the United States, and European countries initiating new lockdowns with surges of infections spreading, an imminent return to cruise-ship travel remains in doubt.
The no-sail order had been extended several times since March but is set to expire on Saturday.
The C.D.C.’s website says that scientific evidence suggests cruise ships — which bring travelers from around the world together to live in close quarters with crew members, where social distancing is hard to maintain — “pose a greater risk of Covid 19 transmission than other settings,” and that outbreaks onboard cruise ships “pose a risk for rapid spread of disease beyond the voyage and into communities across the globe.”